Everything about this midtown spa is comfortable: the heated neck pillow and mug of hot chocolate when you arrive, the couch where you sit for your manicure and pedicure. None of it is fancy, and that's fine with us. Our only complaint: The spa didn't have much in the way of trendy shades. But Balaban was so eager to please that she let us pick a deep red Chanel polish from her personal stash and wear the spa's flip-flops home (she only asked that we return them). And we will be returning: Our pedicure was perfect, and our manicure lasted for a full week and a half.

We're ashamed to admit how bad it had gotten. Our calluses had calluses, and two of our fingernails were so split that Cianciotto, who has tended to Kelly Preston and Barbara Bush, had to pry off the Band-Aids before getting to work. She filed, scrubbed, and generally performed a beauty intervention on our fingernails until they were almost unrecognizable—in a good way. Then she moved on to our sorry feet. Cianciotto won't touch razors. Instead, she rubbed our soles with a dose of sloughing lotion made with olive pits and peppermint, and then worked her nail voodoo with a special buffer that abolishes all ridges. The finale, an intense reflexology massage, made us feel utterly and unspeakably serene.

Whoever said that bad things come in threes never stopped by this uptown salon for a simultaneous manicure, pedicure, and blowout. Soedarmadji, our nail technician, steered us away from the dark brown shade we selected, suggesting a deep purple to suit our fair skin. While she filed our toes, Vagias got to work on our blowout, smoothing out every kink. Next, Soedarmadji moved on to our hands, giving our nails a squarish shape to go with our edgy polish. We left with gleaming fingers, toes, and hair—a true triple threat.

A-list actresses and CEOs of beauty companies are flocking to Choi's salon as much for the candlelit decor as for the manicures and pedicures. Sarah Jessica Parker and Iman soak in Choi's Summer Oasis (sliced cucumber, mint leaves, and peppermint essential oil).

We never quite understood why hot milk makes people sleepy—until we ventured into Jin Soon. We soaked our hands in a bowl of warm milk, honey, and grapefruit essence, which felt so calming and hydrating that our manicurist practically had to pry out each hand for filing. When our nails were shaped to the ideal roundness, she massaged a lemon-scented exfoliator up to our elbows, and rubbed our arms and hands again with a velvety moisturizer. After a wrap of steaming towels, she painted on a light pink shade. By the end, we were feeling smooth and ready for a nap.

Never entirely content to sit still, we're even more jumpy during manicures. We finally settled down, however, for a treatment called the Spirit of the Beehive. And it was easy when our hands were first soaked in warm water spiked with peppermint oil, exfoliated with a salt scrub, and then coated with three layers of warm paraffin wax. (Ahh, the beehive! Now we get it.) Gleaming with deep rose polish, our nails never looked better—whether on the go or sitting still.

Our mother always insisted that facials weren't an extravagance, just basic maintenance. Well, Mom would feel at home here, with the white-gloved doormen and slightly stuffy floral decor. She'd appreciate our aesthetician, too, who executed a thorough deep cleaning while delivering no-nonsense instructions to the nail technician grooming our hands and feet. The entire experience felt far more efficient than indulgent, but we were amazed to discover zero redness and no post-facial breakouts (an absolute first for us).

The place: Track lighting dimly illuminates this quiet, spare space, which has a Japanese ambience.What we asked for: A turquoise gel manicure that would last through an upcoming vacation.The extras: Velvet pillows to rest our hands on while they were painted, ceramic mugs of green tea, and peaceful, blissful silence.Bottom line: With a thin paintbrush, our manicurist applied the odorless polish in precise, fine brushstrokes. An extra layer of topcoat produced a superglossy finish that was just as shiny on the flight home.

The big, open space—with modern lighting and royal-blue communal banquettes—looks nothing like a nail salon. A cute final touch: Their in-house mani-cam makes it easy to share your new nails on social media. Beaudreault will do a mashup of two designs from the nail-art menu, experimenting with polish colors until customers are happy with a cool look.

This busy salon has a packed waiting area, and hairstylists' assistants are everywhere. But Binu's sunlit corner is relatively quiet, and the manicurist herself is soft-spoken and deliberate. She made our short nails look elegant, and our polish stayed chip-free for longer than usual (a week and counting). All in all, we felt justified spending more than we typically do on our nails.

Allen is old-school in the best sense: Her manicures are quick and thorough, last well over a week, and involve not a single ingredient that could also be used in a cocktail. This may explain why her clients—including Julia Roberts and Essie Weingarten (of Essie nail polish)—have been loyal for as long as a decade. Her outpost at this charming salon is also a throwback, with clients sharing recommendations for restaurants in Paris and museums in Milan. Not bad for a halfhour.

This TriBeCa nail spa is cooler than most, starting with the nail-polish selection (which includes Chanel's latest shades), iPads to play with during your appointment, and quietly chic slate gray walls. They take clients until 10 P.M., which is especially cool given our work hours. Our gracious, thoughtful technician stopped several times to make sure we were comfortable and put on glasses to inspect our nails closely. She painted two coats of an inky plum on our fingers and a nearly black brown on our toes, and because we didn't have to dig in our purse for money—the spa emailed our receipt, including the tip, to us—we didn't mess up her work.

The name Fleury Rose sounds like it belongs on a perfume bottle, not in rough-and-tumble Bushwick. But Rose, who works at the punky Tomahawk Salon when she isn't busy painting nails for magazines (including this one), has a cool aesthetic that suits her edgy environment. She buffed and shaped our nails into perfect ovals with a diamond file, then applied a pewter shade that she topped with blue and purple dots. Next, she painted on a few layers of topcoat, which created a seamless mosaic effect and a smooth, shiny finish. Two weeks later, strangers are still stopping us on the street to ask who does our nails.

Valley isn't remotely green—a cloud of acetone fumes greeted us at the door. But clearly, this salon's deeply loyal clientele comes for the nail art—not the air quality. Our technician brushed on a clear coat of polish spiked with gold glitter. The result—gilded tips tapering into flickers of light—was breathtaking, in a good way.

Nail technicians from around the world serve as artists-in-residence at this nail salon turned art space. Inside, you'll see projections of quirky, independent films on the walls and a large selection of nail polish from high-end lines (Dior, Deborah Lippmann) and niche ones (Floss Gloss, RGB). Rodriguez painstakingly creates colorful gel designs, which take some time (two hours for a gel manicure is not unheard of), but the results are stunning and one of a kind, and they last a full three weeks.